Navigation services use positional data to locate vehicles or devices. A simple location on its own may not be useful to a user. The location must be matched to a digital map. Map matching is the process used to match the location with a digital map. Algorithms and software are used to associate or match the location with a known position on a map, e.g. the correct road segment.
Map matching is an essential procedure in navigation, traffic evaluation and other location based services. However, evaluation of the map matching quality proves difficult. In a perfect map matching situation, positional data points would be aligned and matched with the correct road segments that a vehicle was actually traversing. However, errors with map matching may occur due to intrinsic positioning inaccuracy, digital map inaccuracy, or terrain induced inaccuracy. When errors occur, locations may not be mapped to the digital map or may be mapped to the wrong road or wrong segment of a road.
In order to test and evaluate map matching algorithms, actual location data is needed. However, ground truth data is difficult to procure, requiring manual observations for each point of data.